Sinop

Bastion overlooking the harbour, first built in the 8th century BC by Hellenistic immigrants from Miletus, but extended and repaired several times, for instance in the 14th century when the Genoese fortified the entire city. From 1887 to 1997 it housed a high security prison, so it features in the works of a dozen Turkish writers whose seditious publications got them slammed in here. You can look around and climb to the rooftop cafe for views. Otherwise not much here, plans for a cultural centre have come to nothing; perhaps it could be an escape room?

Built in 1267 AD in Seljuk style after its predecessor was destroyed, and named after its endower Sultan Alaaddin Kayqubad I (1188–1237). It's been restored several times, the latest in 2008.

This exhibits artefacts found in the area, plus a Seljuk sultana's tomb of 1395 and a temple to Serapis, presumably Roman.

Displays of local culture in the former Aslan Torun mansion.

Scrappy ruin of a Byzantine church, though the chapel vault is still roofed and has frescoes.